Maddox was a four-year starter for the Illini, spending three years at right guard and one season at center. In 2006, Maddox led an offensive line that posted the best rushing numbers in nearly 30 years at Illinois, which resulted in a Big Ten rushing title. With an average of 188.8 yards rushing per game, the team led the Big Ten, ranked 10th in the nation and recorded its best average since the 1978 season.
As a staple on the offensive line, Maddox started 45 games at Illinois, all but one of his collegiate career. He was a freshman All-American and was twice named the team's Outstanding Offensive Lineman.